71. ______ (not swim) in the river. It's too dangerous. (危险)

70. There ______ (be) a pen and some pencils in my pencil-box.

用各题中所给动词的适当形式填空，使其意思完整与正确。

69. Let's go and ______ (play) football.

68. Is this bottle full? (用empty将原句改为选择疑问句)

______ this bottle full ______ empty?

67. There are about fifty teachers in our school. (就划线部分提问)

______ ______ teachers ______ ______ in our school?

66. Li Ming is doing his homework now. (对划线部分提问)

______ Li Ming ______ now?

65. There are some flowers in the picture. (改为一般疑问句)

______ there ______ flowers in the picture?

64. Those are empty boxes. (改为单数)

______ ______ empty ______.

63. Don't give him the ruler. (改为肯定句)

______ him the ruler.

62. There is some water in the bottle. (改为否定句)

There ______ ______ water in the bottle.